Question

Let \(T\) be the set of all triangles in a plane, with \(T_1RT_2\) defined by “\(T_1\) is congruent to \(T_2\).” Why is this relation reflexive?

Options

• Congruence is defined only between different triangles

• A triangle is greater than itself

• Every triangle is congruent to a different triangle

• Every triangle is congruent to itself

Answer 1

Reflexivity requires each triangle to be related to itself. Since every triangle is congruent to itself, the congruence relation on \(T\) is reflexive.